2010 Camaro SS Project Car Twin Disc Clutch - Disc Jockeying

It was Peter Parker that said, With great power comes great responsibility. And while he was waxing poetic about the superhero gig, he just as well might have been talking about hot rodding. The fact is that this hobby isn’t just about building big-power engines, it’s also making sure that the rest of the car can handle the extra ponies. When GM built our ’10 SS Camaro, now officially named Project CP/28, it was their responsibility to ensure that the drivetrain could support the stock power output of the LS3. Once we boosted the power up to 660 rear-wheel horsepower, that responsibility fell on us. Since dropping in the 416 stroker, we’ve upgraded the axles and felt that our single-disc Centerforce clutch was still up to the challenge of launching a 4,000-pound car spitting out 609 lb-ft of torque.

2/19

All was well with the new engine and we were looking forward to some drag racing at the Holley LS Fest last September. Yancy Johns, the car’s owner, was having a blast and pretty much beating the ever lovin’ snot out of the SS. But after a few runs he started having trouble getting the car to shift. The problem got progressively worse until Yancy proclaimed, Just one more run! Well, that was the proverbial straw and our Camaro decided to sit out the rest of the event. At first we thought that the sticky tires and VHT-prepped drag strip had simply overwhelmed the single-disc, dual-friction clutch, so we made a call to Will Baty over at Centerforce clutches. He told us about a new twin-disc clutch they were getting ready to release. The problem was that we had another event to run the next week, so Centerforce built us one of the first units and pony expressed it out to the event in Pigeon Forge, Tennessee.

3/19

Now Will was pretty pumped up on this new twin-disc clutch and regaled us with stories about how it required very little pedal effort and how quiet and rattle-free it was. We’ve dealt with a lot of twin-disc clutches in the past so these claims were filed in the we’ll believe it when we see it category. According to Will, The DYAD DS Drive system is a unique patent pending design in the world of multi-disc clutches. This new clutch system is rated to hold 1,300 lb-ft of torque at the crankshaft.

4/19

With a new clutch on the way, we set about doing an autopsy on our stricken Camaro. What we found vindicated the single-disc clutch we were running, and to be honest it embarrassed us a bit. Turned out that when we installed the new stroker we used the wrong pilot bearing. This left the TR6060’s input shaft poorly supported and that’s what led to the failure. In our defense, it was the first ’10 we had done, and all of our other LS-equipped cars ran the smaller pilot. Live and learn as they say. Since the new clutch was on the way, we figured we would see if it lived up to the high praise that Will had heaped upon it. Besides, our 416 LS3 is pumping out in excess of 700 lb-ft of torque at the crank and the extra holding capacity of the new clutch was needed anyway.

5/19

With this new clutch, maybe we'll dial up the boost just a touch.

Steven Rupp

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2010 Camaro SS Project Car Twin Disc Clutch - Disc Jockeying

Bill Howell, one of the founding members of the Pro Touring movement, was nice enough to let us use his shop, tools, and lift to do the repairs on the ’10. Tom McBride, owner of HC Automotive, also lent us a hand, along with transmission wizard Steve Fuhrman.

Behold the carnage. On the right is a new GM clutch slave, and on the right is the one we violated. Since the input shaft wasn’t fully supported by the pilot, it wobbled inside the tube creating tremendous heat. Eventually it melted the aluminum tube along with the bearing. We don’t think this is covered by warranty.

After inspecting the input shaft we were a bit disheartened. Fortunately, it looked a lot worse than it was and the shaft was merely smeared with melted aluminum. Tom simply scraped the soft aluminum off the steel shaft and cleaned it up with some low-grit sandpaper.

When the slave started to go, it caused the clutch to slip badly. This created insane amounts of heat as evidenced by the surfaces of the old clutch. But other than that the old dual-friction clutch was fine and we sent it back to Centerforce for some refurbishment TLC. It’s a great clutch, so look for it to show up in another of our project cars.

The new DYAD DS twin-disc Centerforce clutch kit (PN 04614842, $1,550) is a thing of beauty. This was one of their first units produced and when it arrived via second-day air the paint was still a bit sticky.

Every DYD DS clutch that ships from Centerforce comes with what they call a “birth certificate” specific to that unit. It gives all sorts of helpful data like compression depth, travel to release, average clamp load, and most importantly, the average torque holding capacity. In this case, it’s an impressive 1,363 pounds.

Just as the name implies, a twin-disc clutch utilizes two discs separated by what’s called a floater. In past designs it was difficult to get all the various parts properly aligned and the floater had a tendency to make quite a racket. Centerforce solved the alignment issue by having the floater and second disc “carried” by the main drive disc.

As we said before, there are two pilot bearings that can be used in LS/manual trans applications. The one on the left is what we typically use in almost all of our LS swap endeavors. But with the ’10 TR6060 it’s imperative that the roller bearing on the left (GM PN 12557583) be used.

Aluminum flywheels are great for saving weight and getting those revs up quickly, but they have downsides in terms of expansion and durability. Centerforce’s solution was to lighten up a steel flywheel. By removing weight from the outer edge, the flywheel gains much of the benefit found in an aluminum offering. As Centerforce’s Will Baty relayed, “The entire assembly weighs 45.8 pounds, and although the flywheel is made of steel, it has a low-inertia design. We removed 5 pounds of weight from the outer edge of the flywheel, drastically reducing the inertia; allowing the flywheel to have the same inertia as an aluminum flywheel.” While our old dual-friction clutch called for GM torque-to-yield bolts, this one came with high-strength ARP fasteners. You can also spy our shiny new, and correctly sized, roller pilot bearing.

As Will told us, “The DYAD DS is a ‘true sprung’ hub design with the main drive disc built from chromoly steel. The drive disc also has over an inch of spline engagement for stability and strength. The six outer lugs on the driven disc drive the second “floater” disc for positive but smooth engagement.”

The floater then went on and was held in place by the three lugs on the flywheel. Centerforce marked both of these parts with machinist’s ink to let us know how to orientate them. This is important since the pieces are balanced together as a unit.

This is the part we thought was really cool. The floating disc is held by six drive pins rather than on the input shaft of the transmission. This meant aligning the clutch parts was a snap.

Twin discs are known for having rattles caused by the floater and second disc moving about when not under load. Will explained how Centerforce tackled this problem. “The pressure plate uses Centerforce’s patented ‘Ball Bearing’ design for great pressure and low pedal effort. We also incorporated what we call ‘Anti-Rattle’ tabs, which prevent the floater from rattling, a common noise you hear with a traditional multi-disc clutches.”

With all the discs in place, Tom could go ahead and install the pressure plate and secure it with the included high-strength fasteners. Normally a twin-disc clutch is challenging to align, but since all the parts are carried on a common splined shaft, it wasn’t any harder than doing a single disc. And unlike a single disc, this clutch can handle up to 1,300 lb-ft of torque at the crank.

Before stabbing the Tremec TR6060 trans back into the Camaro, we installed a new GM slave and throwout bearing assembly onto the cleaned up input shaft.

Tom and Steve then got our Camaro back on the road and ready to hit the autocross that weekend. In terms of functionality, we were blown away by the new clutch. When we first depressed the clutch, the effort was so minimal that we actually thought there was a problem, but that’s how it was designed to be. Shifting the car is pure joy and we haven’t heard any of the rattles that we had come to expect with twin-disc clutches. Seems like this time the reality lived up to the hype.

See how far a few body panels and some paint went in transforming our 2010 Camaro SS project car into a show stopper! Check out detailed images and captions of the entire paint & body modification process at Camaro Performers Magazine. » Read More